Conventionally in production of semiconductor devices, microfabrication is performed by lithography using a photoresist composition. The microfabrication is a processing method of forming a thin film of the photoresist composition on a substrate being processed such as a silicon wafer, irradiating the workpiece with an active ray such as ultraviolet light through a mask pattern having a pattern for a semiconductor device, and developing the workpiece, followed by etching the substrate being processed such as a silicon wafer using the obtained photoresist pattern as a protective layer. However, in recent years, the degrees of integration of semiconductor devices are progressively enhanced and active rays having shorter wavelengths are increasingly used accompanied with replacement of a KrF excimer laser (248 nm) by an ArF excimer laser (193 nm). Along with this trend, influences of an active ray that is diffuse reflected from a substrate and of a standing wave are becoming serious problems. Hence, studies have been widely conducted on a method of providing an anti-reflective coating (Bottom Anti-Reflective Coating, BARC) between a photoresist and a substrate being processed.
By the way, as the trend toward finer resist patterns progresses, a resolution problem and a problem that resist patterns collapse after development will occur, and thinner-film resists will be desired. Because of this tendency, it becomes difficult to obtain a resist pattern having a film thickness that is adequate for substrate processing, and a demand is growing for a process to provide not only a resist pattern but also a resist underlayer film formed between a resist and a semiconductor substrate being processed with a function to serve as a mask on substrate processing. As the resist underlayer film for such a process, resist underlayer films for lithography having dry etching selectivity similar to that of a resist, resist underlayer films for lithography having dry etching selectivity smaller than that of a resist, and resist underlayer films for lithography having dry etching selectivity smaller than that of a semiconductor substrate are being required instead of conventional resist underlayer films having high etch rate properties (having high etching rates).
In order to satisfy these requirements, it is disclosed to subject an aliphatic epoxy polymer to a reaction with anthracenecarboxylic acid and use the obtained polymer as an anti-reflective coating for a resist underlayer (see Patent Document 1).